Waleli!
(Greetings in Zanaki)
• Do Now:
– Take out Lab notebook
– Take out Deadly Picnic
• Agenda:
– Body farm video
– Types of physical Evidence
• HW:
– Notes on p83-90
– 3-2-1 bridge with notes
Deadly Picnic
• Elaine
• Answers will vary but may include:
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•
Rita: never wears lipstick; lives in the country
Lauren: has large feet; allergic to daisies
Gail hates yellow at aerobics on Friday, nonsmoker
Janice teaches aerobics on Friday night, hates yellow, nonsmoker
Peggy: allergic to grapes; never wears lipstick
Lives downtown; has small feet
• Stories will vary See example below:
Elaine and Mr. Brooks had a date for a picnic on Friday night. Elaine
volunteered to bring the sheet for the picnic if Mr. Brooks provided the food
and wine. He picked up Elaine at about 6:00 RM. They went to the picnic area
out in the country. Elaine was jealous of Mr. Brooks’s relationship with her
roommate. She took a gun to the picnic for revenge. Elaine and Mr. Brooks
walked down to the field of daisies and spread out their sheet for the food.
They got everything out and began eating and drinking. Elaine took out the
gun and shot Mr. Brooks in the head. She ran back up to the road where they
left his car. She drove herself back to town and abandoned his car in a parking
lot that was vacant. From here she walked a few blocks to her apartment.
Characteristics of evidence
• Class characteristics
features that place the
item into a specific
category
• Individual
characteristics
features that distinguish
one item from another
of the same type
Skeletal Remains
• Forensic anthropologists analyze skeletal remains to
determine four characteristics for a victim: age, sex, race,
and stature (height/build).
 Sex –examining the pelvis, humerus, and
femur
 Age and stature – analyzing the development
of the teeth, bone growth, and the length of specifc
bones, such as the femur.
 Race – analyzing the skull for characteristics
that are common among people of different races.
• DNA samples can be collected from bone, teeth, and
hair to provide clues to a person’s identity.
Scientists may also be able to gain clues as to a person’s
past, recent injuries, or the cause of death based on bone
fractures and other signs of trauma.
Source: http://www.crime-scene-investigator.net/excavation.html
Images: http://www.celticnz.org/images/Feedback/SkullSkeleton.JPG and http://www.legacyhealth.org/images/Housecalls/claviclefx.jpg
What do forensic anthropologists do?
Generally, forensic anthropologists DO NOT do any of the following:
• Collect trace evidence (hair, fibers)
• Run DNA tests
• Analyze ballistics or weapon evidence
• Analyze blood spatter
• Conduct autopsies
What a forensic anthropologist does DO to aid in a case:
• Goes to a crime scene to assist in the collection of human remains
• Cleans up the bones so that they may be looked at
• Analyzes skeletal remains to establish the profile of the individual
• Looks at trauma evident on the bones to establish the pathway of a bullet or the
number of stab wounds
• Works with a forensic odontologist (dentist) to match dental records
• Testifies in court about the identity of the individual and/or the injuries that
might be evident in the skeleton
Source: http://web.utk.edu/~fac/forensic.shtml
Body Fluids
• Blood, semen, saliva, sweat, and urine can be analyzed to give investigators information
about the crime as well as its victim or the suspect.
• Chemicals and ultra violet light
• find body fluid evidence
• Areas with potential evidence are swabbed, bagged and collected in vials, which
are air tight and have a low risk of cross contamination.
Examples:
 Vomit and urine can be used to test for alcohol,
drugs, and poisons.
 Cigarette butts may contain dried saliva.
 Semen containing sperm is valuable for DNA
analysis.

Blood can provide DNA evidence and blood
spatter can provide clues about the crime.
Source: http://www.virtualsciencefair.org/2004/fren4j0/public_html/trace_evidence.htm
Images: http://www.trutv.com/library/crime/criminal_mind/forensics/chinatown_widow/4.html
Ù Conventional serology:
ò presence of blood in stains
ò species identification and
ABO grouping
ò is not adequately
informative to positive
identify a person
Ù DNA analysis can associate
victim and/or suspect with each
other or with the crime scene
Ù BLOODSTAIN PATTERNS
ò additional information
SEM: erythrocytes & lymphocytes
• BODY TISSUES
Ù organ samples collected at
autopsy, including blood,
urine and stomach contents
• DRUGS & CONTROLLED
SUBSTANCES
ò toxicological analysis
ò volatile compounds (ethanol,
methanol, isopropanol)
ò heavy metals (arsenic)
ò nonvolatile organic compounds
(drugs of abuse, pharmaceuticals)
ò miscellaneous (strychnine,
cyanide)
ò trace drug presence, identity,
and quantity
Ù plant materials, powders,
tablets, capsules
Black tar heroine wrapped in cellophane
• Wounds
• matched to weapons or tool marks on the
weapon.
• Investigators may also be able to
determine the weapon's size, shape, and
length.
• Analysis of a wound may provides clues:
• to a victim’s injuries
• characteristics of the suspect (left-handed,
right-handed, height, etc.)
• positions of the victim and suspect at the
time of the incident.
Image: (Bottom Left): http://dofs.gbi.georgia.gov/vgn/images/portal/cit_11783501/81672146questioned%20document.jpg
• DOCUMENTS
Ù ransom note or other document to
find clues link it to a crime scene or
a specific suspect
Ù analyze the type of paper used,
printing method or handwriting
style, and type of ink.
ò typed, handwritten and printed
materials for evidence of forgery
ò indented writings, obliterated or
altered writings, used carbon paper,
burned or charred paper
Ù paper and ink analysis
Ù handwriting comparison to
determine authenticity
Obliterated writing examination
Explosives
•determine its chemical composition to identify the type of
explosive used and its origin.
• Traces of explosives found on a suspect’s clothing, skin, hair, or
other objects may be matched to explosives from the crime scene.
• Materials used to make an explosive device will be compared to
evidence found in the suspect’s possession to confirm a match.
Image: http://www.state.nj.us/njsp/divorg/invest/criminalistics.html
Dust & Dirt
• Dust, dirt, or sand evidence can reveal where a
person has traveled and may be picked up at a
crime scene or left behind.
Microscopic Image of Sand
• Investigators examine the samples for chemical
composition, pollen, plant material, and other
organic matter to find links to a specific crime
scene.
Fingerprints
• There are 3 types of fingerprint patterns: arches, loops, and whorls.
Investigators also identify unique ridge characteristics in a fingerprint that
can be used to identify a suspect or victim.
• AFIS (Automated Fingerprint Identification System) is a database used
by investigators at local, state, and national levels to search for matches to
fingerprints found at a crime scene.
Images: http://www.npsg.uwaterloo.ca/resources/images/microscope/Sand%200004.jpg
Types of physical evidence
• SOILS & MINERALS
ò comparison between two or
more soils to determine if
they share a common origin
ò color, texture, composition
comparison
Layers of soil exposed at a grave site. Each
layer must be sampled
• WOOD
ò place the suspect at the
crime scene
ò side or end matching,
fracture matching and
species identification.
Cross-section - Xylem
Types of physical evidence
• FINGERPRINTS
ò the strongest possible
evidence of a person’s
identity
Fingerprint Matching
• FIRE DEBRIS &
EXPLOSIVES RESIDUE
EXAMINATIONS
ò identification of accelerants
and explosive residues
Unburned accelerator liquid on a soot covered carpet
Ballistics
• Chemical tests can reveal gunshot residue (GSR) on:
• hands, face, or clothing of a victim or suspect
• indicate how close a person was to a fired gun.
• Rifling (grooves) in a gun barrel causes distinctive grooves, indentations and scratches
upon fired bullets, which can be matched to the weapon that fired them.
• Police are able to search the Integrated Ballistics Identification System (IBIS) database
to compare markings from bullets, cartridge cases, and shotgun shells to ballistic evidence.
Did you know?
Caliber (handguns & rifles) or gauge
(shotguns) refers to the size of the
internal diameter of a gun’s barrel.
Investigators can compare the
striations on bullets to see if
they match.
Image: http://www.geocities.com/j_ksinha/img/mid1.gif
• FIREARMS & AMMUNITION
Ù individual microscopic marks
ò identification, source,
operability of firearms.
Ù detection and characterization
of gunpowder residues
Ù muzzle-to-garments distance
estimation
Photomicrograph: test
bullet - questioned bullet
GLASS FRAGMENTS
ò Cause of breakage
ò Direction of breakage force
ò Physical fitting
ò Glass fragment comparisons
ò determine its color, surface characteristics, tint, thickness, density, chemical
composition, and refractive index (RI).
Magnified image of glass fragments
The pattern of cracks in a windshield fracture
can reveal information about speed, occupant
position, and angle of impact.
Images: http://www.rsc.org/images/b606109e-300-(FOR-TRIDION)%20(iStockphotos)_tcm18-68354.jpg, http://www.mtcforensics.com/investigation.html
• HAIRS
Ù hairs analysis can
determine
ò
ò
ò
ò
ò
human/animal
race
body area
Image
cosmetic treatments Microscopic
of Hairs & Fibers
method of removal (crushed,
cut, burned, forcibly removed,
fallen out naturally)
Ù morphological features ò can associate a hair to a
person
Ù DNA analysis
ò positive identification
Ù toxicological
ò presence of drugs and poisons
examination
ò type (clothing, carpeting,
furniture, beds, and blankets)
 FIBERS
ò color, composition construction
ò natural fibers from plants or animals
or synthetic fibers that are manmade.
Two matching hairs
identified with the
comparison microscope
Flax fibers viewed with
polarized light
Impression Evidence
Shoeprints & Tire Tracks
• photographed, lifted with tape, or cast with plaster
• Investigators will examine the evidence to identify:
• the brand of shoe or tire
• based on its tread pattern and other physical
features
• Shoes and tires will also show wear patterns
as well as other features (scratches, nicks,
and cuts)
Shoeprint
collected
using a
gelatin lifter.
Bite Marks
• Each of the 32 teeth in humans is unique due to age and wear.
• Impressions and photographs of bite marks left on a victim,
assailant, or other object at a crime scene
Tool Marks
• Tiny nicks and chips form on the edges of a tool as it is used
• Tools may also pick up traces:
• blood or other substances
• have fingerprints that can be lifted.
Images: http://www.wrongfulconvictionlawsuitdefense.com/uploads/image/28santos_600.jpg, http://www.dps.state.ia.us/DCI/Crime_Lab/images/toolmarks.jpg, &
http://www.masterpiecestudios.com/images/171463.gif
Paint
• Physical and chemical analysis of paint evidence (chips or residue) can indicate:
• class, such as automobile paint, house paint, nail polish, etc.
• compared to 40,000 different types of paint classified in a database
• Paint evidence can also indicate
• individual characteristics if an investigator is able to find similarities
between two samples, such as the color, number of layers, chemical
composition, or a physical match between the edges of two paint chips –
one from a tool and one from a crime scene.
Paint Transfer on a Car
Did you know?
Most paint evidence submitted to a lab will come
from hit-and-run cases involving automobiles.
Paint Layers
Physical Match of
Paint Chip Edges
Images: http://www.state.nj.us/njsp/divorg/invest/criminalistics.html
• PAINT & PAINT PRODUCTS
Ù analysis and comparison of
paint transferred from the
surface of an object to another
during the commission of a
crime:
ò Suspect vehicle impacting a
victim vehicle; a pedestrian or a
stationary object
ò Tool impacting stationary object
Ù Paint databases can help
identify the year, make and/or
color of a motor vehicle from a
chip of paint left at the scene.
Paint Layers on Wood Surface
Types of physical evidence
• TOOLMARK IDENTIFICATION
ò microscopic side-by-side
comparison
ò attempts to link a particular tool
with a particular mark to the
exclusion of any other tool
• ROPE & CORDAGE
ò composition, construction, color
and diameter
Spacing between teeth in gripping -major
role in toolmark examinations
òmanufacturer
Insects
• Flies, beetles, and other insects
can provide useful clues about a corpse.
• Forensic entomologists use factors to
estimate PMI (postmortem interval)
•weather conditions
•location
•condition of the body
•life cycles of insects
DNA
• Investigators can extract DNA from almost any tissue including:
• hair
• fingernails
• bones
• teeth
• body fluids
CODIS (Combined DNA Index System) is a database maintained by the
FBI that is used to find matches to unknown DNA samples from a
crime scene.
Images: http://biology.arizona.edu/sciconn/lessons2/Vuturo/vuturo/photos/desmus.gif